Almost all present motion picture theaters project 24 new frames per second on the screen, with each frame being interrupted once. This results in showing 48 images per second (with pairs of successive images being identical), which avoids the sensing of flickering by the audience. It has been found that greater vividness and realism are achieved by projecting far more than 24 new frames per second. For example, U.S. Pat. No. 4,477,160 describes a motion picture system wherein60 new frames per second are projected onto a screen. In order to permit a motion picture taken with a camera at a high frame rate such as 60 fps, to be shown in a conventional motion picture theater which can only operate at 24 fps, a conversion of the 60 fps to the 24 fps rate is required.
One simple way of converting a strip of film intended for showing at a high frame rate such as 60 fps to a film for projecting at a low frame rate such as 24 fps, is to alternately copy every second and every third frame of the 60 fps film onto areas of the 24 fps film. However, even for film frames of the same size, this results in the potential loss of two-thirds of the information available on the 60 fps film. A conversion technique which retains more of the information available in the high frame rate film, when converting it to a lower frame rate, would result in a superior lower frame rate film and a superior motion picture image when the lower frame rate film is projected on a screen.